Touch input devices have been widely used in human-machine interaction applications such as smart phones, e-books, tablets and laptops. The touch input device is generally based on capacitive touch sensors which are competent in sensing of a position and track of a touch operation, but not in detection of a pressure applied in a pressing operation.
Touch input devices based on pressure sensors have been developed. Although they are effective, there is still a need for alternatives to traditional touch input devices that are based on pressure sensors.